net/core/flow_dissector.c

   1 #include <linux/kernel.h>
   2 #include <linux/skbuff.h>
   3 #include <linux/export.h>
   4 #include <linux/ip.h>
   5 #include <linux/ipv6.h>
   6 #include <linux/if_vlan.h>
   7 #include <net/dsa.h>
   8 #include <net/dst_metadata.h>
   9 #include <net/ip.h>
  10 #include <net/ipv6.h>
  11 #include <net/gre.h>
  12 #include <net/pptp.h>
  13 #include <net/tipc.h>
  14 #include <linux/igmp.h>
  15 #include <linux/icmp.h>
  16 #include <linux/sctp.h>
  17 #include <linux/dccp.h>
  18 #include <linux/if_tunnel.h>
  19 #include <linux/if_pppox.h>
  20 #include <linux/ppp_defs.h>
  21 #include <linux/stddef.h>
  22 #include <linux/if_ether.h>
  23 #include <linux/mpls.h>
  24 #include <linux/tcp.h>
  25 #include <net/flow_dissector.h>
  26 #include <scsi/fc/fc_fcoe.h>
  27 #include <uapi/linux/batadv_packet.h>
  28 #include <linux/bpf.h>
  29
  30 static DEFINE_MUTEX(flow_dissector_mutex);
  31
  32 static void dissector_set_key(struct flow_dissector *flow_dissector,
  33                               enum flow_dissector_key_id key_id)
  34 {
  35         flow_dissector->used_keys |= (1 << key_id);
  36 }
  37
  38 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
  39                              const struct flow_dissector_key *key,
  40                              unsigned int key_count)
  41 {
  42         unsigned int i;
  43
  44         memset(flow_dissector, 0, sizeof(*flow_dissector));
  45
  46         for (i = 0; i < key_count; i++, key++) {
  47                 /* User should make sure that every key target offset is withing
  48                  * boundaries of unsigned short.
  49                  */
  50                 BUG_ON(key->offset > USHRT_MAX);
  51                 BUG_ON(dissector_uses_key(flow_dissector,
  52                                           key->key_id));
  53
  54                 dissector_set_key(flow_dissector, key->key_id);
  55                 flow_dissector->offset[key->key_id] = key->offset;
  56         }
  57
  58         /* Ensure that the dissector always includes control and basic key.
  59          * That way we are able to avoid handling lack of these in fast path.
  60          */
  61         BUG_ON(!dissector_uses_key(flow_dissector,
  62                                    FLOW_DISSECTOR_KEY_CONTROL));
  63         BUG_ON(!dissector_uses_key(flow_dissector,
  64                                    FLOW_DISSECTOR_KEY_BASIC));
  65 }
  66 EXPORT_SYMBOL(skb_flow_dissector_init);
  67
  68 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
  69                                        struct bpf_prog *prog)
  70 {
  71         struct bpf_prog *attached;
  72         struct net *net;
  73
  74         net = current->nsproxy->net_ns;
  75         mutex_lock(&flow_dissector_mutex);
  76         attached = rcu_dereference_protected(net->flow_dissector_prog,
  77                                              lockdep_is_held(&flow_dissector_mutex));
  78         if (attached) {
  79                 /* Only one BPF program can be attached at a time */
  80                 mutex_unlock(&flow_dissector_mutex);
  81                 return -EEXIST;
  82         }
  83         rcu_assign_pointer(net->flow_dissector_prog, prog);
  84         mutex_unlock(&flow_dissector_mutex);
  85         return 0;
  86 }
  87
  88 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
  89 {
  90         struct bpf_prog *attached;
  91         struct net *net;
  92
  93         net = current->nsproxy->net_ns;
  94         mutex_lock(&flow_dissector_mutex);
  95         attached = rcu_dereference_protected(net->flow_dissector_prog,
  96                                              lockdep_is_held(&flow_dissector_mutex));
  97         if (!attached) {
  98                 mutex_unlock(&flow_dissector_mutex);
  99                 return -ENOENT;
 100         }
 101         bpf_prog_put(attached);
 102         RCU_INIT_POINTER(net->flow_dissector_prog, NULL);
 103         mutex_unlock(&flow_dissector_mutex);
 104         return 0;
 105 }
 106 /**
 107  * skb_flow_get_be16 - extract be16 entity
 108  * @skb: sk_buff to extract from
 109  * @poff: offset to extract at
 110  * @data: raw buffer pointer to the packet
 111  * @hlen: packet header length
 112  *
 113  * The function will try to retrieve a be32 entity at
 114  * offset poff
 115  */
 116 static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff,
 117                                 void *data, int hlen)
 118 {
 119         __be16 *u, _u;
 120
 121         u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u);
 122         if (u)
 123                 return *u;
 124
 125         return 0;
 126 }
 127
 128 /**
 129  * __skb_flow_get_ports - extract the upper layer ports and return them
 130  * @skb: sk_buff to extract the ports from
 131  * @thoff: transport header offset
 132  * @ip_proto: protocol for which to get port offset
 133  * @data: raw buffer pointer to the packet, if NULL use skb->data
 134  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
 135  *
 136  * The function will try to retrieve the ports at offset thoff + poff where poff
 137  * is the protocol port offset returned from proto_ports_offset
 138  */
 139 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
 140                             void *data, int hlen)
 141 {
 142         int poff = proto_ports_offset(ip_proto);
 143
 144         if (!data) {
 145                 data = skb->data;
 146                 hlen = skb_headlen(skb);
 147         }
 148
 149         if (poff >= 0) {
 150                 __be32 *ports, _ports;
 151
 152                 ports = __skb_header_pointer(skb, thoff + poff,
 153                                              sizeof(_ports), data, hlen, &_ports);
 154                 if (ports)
 155                         return *ports;
 156         }
 157
 158         return 0;
 159 }
 160 EXPORT_SYMBOL(__skb_flow_get_ports);
 161
 162 static void
 163 skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type,
 164                                    struct flow_dissector *flow_dissector,
 165                                    void *target_container)
 166 {
 167         struct flow_dissector_key_control *ctrl;
 168
 169         if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL))
 170                 return;
 171
 172         ctrl = skb_flow_dissector_target(flow_dissector,
 173                                          FLOW_DISSECTOR_KEY_ENC_CONTROL,
 174                                          target_container);
 175         ctrl->addr_type = type;
 176 }
 177
 178 void
 179 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
 180                              struct flow_dissector *flow_dissector,
 181                              void *target_container)
 182 {
 183         struct ip_tunnel_info *info;
 184         struct ip_tunnel_key *key;
 185
 186         /* A quick check to see if there might be something to do. */
 187         if (!dissector_uses_key(flow_dissector,
 188                                 FLOW_DISSECTOR_KEY_ENC_KEYID) &&
 189             !dissector_uses_key(flow_dissector,
 190                                 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) &&
 191             !dissector_uses_key(flow_dissector,
 192                                 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) &&
 193             !dissector_uses_key(flow_dissector,
 194                                 FLOW_DISSECTOR_KEY_ENC_CONTROL) &&
 195             !dissector_uses_key(flow_dissector,
 196                                 FLOW_DISSECTOR_KEY_ENC_PORTS) &&
 197             !dissector_uses_key(flow_dissector,
 198                                 FLOW_DISSECTOR_KEY_ENC_IP) &&
 199             !dissector_uses_key(flow_dissector,
 200                                 FLOW_DISSECTOR_KEY_ENC_OPTS))
 201                 return;
 202
 203         info = skb_tunnel_info(skb);
 204         if (!info)
 205                 return;
 206
 207         key = &info->key;
 208
 209         switch (ip_tunnel_info_af(info)) {
 210         case AF_INET:
 211                 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 212                                                    flow_dissector,
 213                                                    target_container);
 214                 if (dissector_uses_key(flow_dissector,
 215                                        FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS)) {
 216                         struct flow_dissector_key_ipv4_addrs *ipv4;
 217
 218                         ipv4 = skb_flow_dissector_target(flow_dissector,
 219                                                          FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS,
 220                                                          target_container);
 221                         ipv4->src = key->u.ipv4.src;
 222                         ipv4->dst = key->u.ipv4.dst;
 223                 }
 224                 break;
 225         case AF_INET6:
 226                 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 227                                                    flow_dissector,
 228                                                    target_container);
 229                 if (dissector_uses_key(flow_dissector,
 230                                        FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS)) {
 231                         struct flow_dissector_key_ipv6_addrs *ipv6;
 232
 233                         ipv6 = skb_flow_dissector_target(flow_dissector,
 234                                                          FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS,
 235                                                          target_container);
 236                         ipv6->src = key->u.ipv6.src;
 237                         ipv6->dst = key->u.ipv6.dst;
 238                 }
 239                 break;
 240         }
 241
 242         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_KEYID)) {
 243                 struct flow_dissector_key_keyid *keyid;
 244
 245                 keyid = skb_flow_dissector_target(flow_dissector,
 246                                                   FLOW_DISSECTOR_KEY_ENC_KEYID,
 247                                                   target_container);
 248                 keyid->keyid = tunnel_id_to_key32(key->tun_id);
 249         }
 250
 251         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_PORTS)) {
 252                 struct flow_dissector_key_ports *tp;
 253
 254                 tp = skb_flow_dissector_target(flow_dissector,
 255                                                FLOW_DISSECTOR_KEY_ENC_PORTS,
 256                                                target_container);
 257                 tp->src = key->tp_src;
 258                 tp->dst = key->tp_dst;
 259         }
 260
 261         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_IP)) {
 262                 struct flow_dissector_key_ip *ip;
 263
 264                 ip = skb_flow_dissector_target(flow_dissector,
 265                                                FLOW_DISSECTOR_KEY_ENC_IP,
 266                                                target_container);
 267                 ip->tos = key->tos;
 268                 ip->ttl = key->ttl;
 269         }
 270
 271         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_OPTS)) {
 272                 struct flow_dissector_key_enc_opts *enc_opt;
 273
 274                 enc_opt = skb_flow_dissector_target(flow_dissector,
 275                                                     FLOW_DISSECTOR_KEY_ENC_OPTS,
 276                                                     target_container);
 277
 278                 if (info->options_len) {
 279                         enc_opt->len = info->options_len;
 280                         ip_tunnel_info_opts_get(enc_opt->data, info);
 281                         enc_opt->dst_opt_type = info->key.tun_flags &
 282                                                 TUNNEL_OPTIONS_PRESENT;
 283                 }
 284         }
 285 }
 286 EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
 287
 288 static enum flow_dissect_ret
 289 __skb_flow_dissect_mpls(const struct sk_buff *skb,
 290                         struct flow_dissector *flow_dissector,
 291                         void *target_container, void *data, int nhoff, int hlen)
 292 {
 293         struct flow_dissector_key_keyid *key_keyid;
 294         struct mpls_label *hdr, _hdr[2];
 295         u32 entry, label;
 296
 297         if (!dissector_uses_key(flow_dissector,
 298                                 FLOW_DISSECTOR_KEY_MPLS_ENTROPY) &&
 299             !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS))
 300                 return FLOW_DISSECT_RET_OUT_GOOD;
 301
 302         hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
 303                                    hlen, &_hdr);
 304         if (!hdr)
 305                 return FLOW_DISSECT_RET_OUT_BAD;
 306
 307         entry = ntohl(hdr[0].entry);
 308         label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
 309
 310         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) {
 311                 struct flow_dissector_key_mpls *key_mpls;
 312
 313                 key_mpls = skb_flow_dissector_target(flow_dissector,
 314                                                      FLOW_DISSECTOR_KEY_MPLS,
 315                                                      target_container);
 316                 key_mpls->mpls_label = label;
 317                 key_mpls->mpls_ttl = (entry & MPLS_LS_TTL_MASK)
 318                                         >> MPLS_LS_TTL_SHIFT;
 319                 key_mpls->mpls_tc = (entry & MPLS_LS_TC_MASK)
 320                                         >> MPLS_LS_TC_SHIFT;
 321                 key_mpls->mpls_bos = (entry & MPLS_LS_S_MASK)
 322                                         >> MPLS_LS_S_SHIFT;
 323         }
 324
 325         if (label == MPLS_LABEL_ENTROPY) {
 326                 key_keyid = skb_flow_dissector_target(flow_dissector,
 327                                                       FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
 328                                                       target_container);
 329                 key_keyid->keyid = hdr[1].entry & htonl(MPLS_LS_LABEL_MASK);
 330         }
 331         return FLOW_DISSECT_RET_OUT_GOOD;
 332 }
 333
 334 static enum flow_dissect_ret
 335 __skb_flow_dissect_arp(const struct sk_buff *skb,
 336                        struct flow_dissector *flow_dissector,
 337                        void *target_container, void *data, int nhoff, int hlen)
 338 {
 339         struct flow_dissector_key_arp *key_arp;
 340         struct {
 341                 unsigned char ar_sha[ETH_ALEN];
 342                 unsigned char ar_sip[4];
 343                 unsigned char ar_tha[ETH_ALEN];
 344                 unsigned char ar_tip[4];
 345         } *arp_eth, _arp_eth;
 346         const struct arphdr *arp;
 347         struct arphdr _arp;
 348
 349         if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP))
 350                 return FLOW_DISSECT_RET_OUT_GOOD;
 351
 352         arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,
 353                                    hlen, &_arp);
 354         if (!arp)
 355                 return FLOW_DISSECT_RET_OUT_BAD;
 356
 357         if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
 358             arp->ar_pro != htons(ETH_P_IP) ||
 359             arp->ar_hln != ETH_ALEN ||
 360             arp->ar_pln != 4 ||
 361             (arp->ar_op != htons(ARPOP_REPLY) &&
 362              arp->ar_op != htons(ARPOP_REQUEST)))
 363                 return FLOW_DISSECT_RET_OUT_BAD;
 364
 365         arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),
 366                                        sizeof(_arp_eth), data,
 367                                        hlen, &_arp_eth);
 368         if (!arp_eth)
 369                 return FLOW_DISSECT_RET_OUT_BAD;
 370
 371         key_arp = skb_flow_dissector_target(flow_dissector,
 372                                             FLOW_DISSECTOR_KEY_ARP,
 373                                             target_container);
 374
 375         memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip));
 376         memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip));
 377
 378         /* Only store the lower byte of the opcode;
 379          * this covers ARPOP_REPLY and ARPOP_REQUEST.
 380          */
 381         key_arp->op = ntohs(arp->ar_op) & 0xff;
 382
 383         ether_addr_copy(key_arp->sha, arp_eth->ar_sha);
 384         ether_addr_copy(key_arp->tha, arp_eth->ar_tha);
 385
 386         return FLOW_DISSECT_RET_OUT_GOOD;
 387 }
 388
 389 static enum flow_dissect_ret
 390 __skb_flow_dissect_gre(const struct sk_buff *skb,
 391                        struct flow_dissector_key_control *key_control,
 392                        struct flow_dissector *flow_dissector,
 393                        void *target_container, void *data,
 394                        __be16 *p_proto, int *p_nhoff, int *p_hlen,
 395                        unsigned int flags)
 396 {
 397         struct flow_dissector_key_keyid *key_keyid;
 398         struct gre_base_hdr *hdr, _hdr;
 399         int offset = 0;
 400         u16 gre_ver;
 401
 402         hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr),
 403                                    data, *p_hlen, &_hdr);
 404         if (!hdr)
 405                 return FLOW_DISSECT_RET_OUT_BAD;
 406
 407         /* Only look inside GRE without routing */
 408         if (hdr->flags & GRE_ROUTING)
 409                 return FLOW_DISSECT_RET_OUT_GOOD;
 410
 411         /* Only look inside GRE for version 0 and 1 */
 412         gre_ver = ntohs(hdr->flags & GRE_VERSION);
 413         if (gre_ver > 1)
 414                 return FLOW_DISSECT_RET_OUT_GOOD;
 415
 416         *p_proto = hdr->protocol;
 417         if (gre_ver) {
 418                 /* Version1 must be PPTP, and check the flags */
 419                 if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY)))
 420                         return FLOW_DISSECT_RET_OUT_GOOD;
 421         }
 422
 423         offset += sizeof(struct gre_base_hdr);
 424
 425         if (hdr->flags & GRE_CSUM)
 426                 offset += FIELD_SIZEOF(struct gre_full_hdr, csum) +
 427                           FIELD_SIZEOF(struct gre_full_hdr, reserved1);
 428
 429         if (hdr->flags & GRE_KEY) {
 430                 const __be32 *keyid;
 431                 __be32 _keyid;
 432
 433                 keyid = __skb_header_pointer(skb, *p_nhoff + offset,
 434                                              sizeof(_keyid),
 435                                              data, *p_hlen, &_keyid);
 436                 if (!keyid)
 437                         return FLOW_DISSECT_RET_OUT_BAD;
 438
 439                 if (dissector_uses_key(flow_dissector,
 440                                        FLOW_DISSECTOR_KEY_GRE_KEYID)) {
 441                         key_keyid = skb_flow_dissector_target(flow_dissector,
 442                                                               FLOW_DISSECTOR_KEY_GRE_KEYID,
 443                                                               target_container);
 444                         if (gre_ver == 0)
 445                                 key_keyid->keyid = *keyid;
 446                         else
 447                                 key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK;
 448                 }
 449                 offset += FIELD_SIZEOF(struct gre_full_hdr, key);
 450         }
 451
 452         if (hdr->flags & GRE_SEQ)
 453                 offset += FIELD_SIZEOF(struct pptp_gre_header, seq);
 454
 455         if (gre_ver == 0) {
 456                 if (*p_proto == htons(ETH_P_TEB)) {
 457                         const struct ethhdr *eth;
 458                         struct ethhdr _eth;
 459
 460                         eth = __skb_header_pointer(skb, *p_nhoff + offset,
 461                                                    sizeof(_eth),
 462                                                    data, *p_hlen, &_eth);
 463                         if (!eth)
 464                                 return FLOW_DISSECT_RET_OUT_BAD;
 465                         *p_proto = eth->h_proto;
 466                         offset += sizeof(*eth);
 467
 468                         /* Cap headers that we access via pointers at the
 469                          * end of the Ethernet header as our maximum alignment
 470                          * at that point is only 2 bytes.
 471                          */
 472                         if (NET_IP_ALIGN)
 473                                 *p_hlen = *p_nhoff + offset;
 474                 }
 475         } else { /* version 1, must be PPTP */
 476                 u8 _ppp_hdr[PPP_HDRLEN];
 477                 u8 *ppp_hdr;
 478
 479                 if (hdr->flags & GRE_ACK)
 480                         offset += FIELD_SIZEOF(struct pptp_gre_header, ack);
 481
 482                 ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset,
 483                                                sizeof(_ppp_hdr),
 484                                                data, *p_hlen, _ppp_hdr);
 485                 if (!ppp_hdr)
 486                         return FLOW_DISSECT_RET_OUT_BAD;
 487
 488                 switch (PPP_PROTOCOL(ppp_hdr)) {
 489                 case PPP_IP:
 490                         *p_proto = htons(ETH_P_IP);
 491                         break;
 492                 case PPP_IPV6:
 493                         *p_proto = htons(ETH_P_IPV6);
 494                         break;
 495                 default:
 496                         /* Could probably catch some more like MPLS */
 497                         break;
 498                 }
 499
 500                 offset += PPP_HDRLEN;
 501         }
 502
 503         *p_nhoff += offset;
 504         key_control->flags |= FLOW_DIS_ENCAPSULATION;
 505         if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 506                 return FLOW_DISSECT_RET_OUT_GOOD;
 507
 508         return FLOW_DISSECT_RET_PROTO_AGAIN;
 509 }
 510
 511 /**
 512  * __skb_flow_dissect_batadv() - dissect batman-adv header
 513  * @skb: sk_buff to with the batman-adv header
 514  * @key_control: flow dissectors control key
 515  * @data: raw buffer pointer to the packet, if NULL use skb->data
 516  * @p_proto: pointer used to update the protocol to process next
 517  * @p_nhoff: pointer used to update inner network header offset
 518  * @hlen: packet header length
 519  * @flags: any combination of FLOW_DISSECTOR_F_*
 520  *
 521  * ETH_P_BATMAN packets are tried to be dissected. Only
 522  * &struct batadv_unicast packets are actually processed because they contain an
 523  * inner ethernet header and are usually followed by actual network header. This
 524  * allows the flow dissector to continue processing the packet.
 525  *
 526  * Return: FLOW_DISSECT_RET_PROTO_AGAIN when &struct batadv_unicast was found,
 527  *  FLOW_DISSECT_RET_OUT_GOOD when dissector should stop after encapsulation,
 528  *  otherwise FLOW_DISSECT_RET_OUT_BAD
 529  */
 530 static enum flow_dissect_ret
 531 __skb_flow_dissect_batadv(const struct sk_buff *skb,
 532                           struct flow_dissector_key_control *key_control,
 533                           void *data, __be16 *p_proto, int *p_nhoff, int hlen,
 534                           unsigned int flags)
 535 {
 536         struct {
 537                 struct batadv_unicast_packet batadv_unicast;
 538                 struct ethhdr eth;
 539         } *hdr, _hdr;
 540
 541         hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), data, hlen,
 542                                    &_hdr);
 543         if (!hdr)
 544                 return FLOW_DISSECT_RET_OUT_BAD;
 545
 546         if (hdr->batadv_unicast.version != BATADV_COMPAT_VERSION)
 547                 return FLOW_DISSECT_RET_OUT_BAD;
 548
 549         if (hdr->batadv_unicast.packet_type != BATADV_UNICAST)
 550                 return FLOW_DISSECT_RET_OUT_BAD;
 551
 552         *p_proto = hdr->eth.h_proto;
 553         *p_nhoff += sizeof(*hdr);
 554
 555         key_control->flags |= FLOW_DIS_ENCAPSULATION;
 556         if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 557                 return FLOW_DISSECT_RET_OUT_GOOD;
 558
 559         return FLOW_DISSECT_RET_PROTO_AGAIN;
 560 }
 561
 562 static void
 563 __skb_flow_dissect_tcp(const struct sk_buff *skb,
 564                        struct flow_dissector *flow_dissector,
 565                        void *target_container, void *data, int thoff, int hlen)
 566 {
 567         struct flow_dissector_key_tcp *key_tcp;
 568         struct tcphdr *th, _th;
 569
 570         if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_TCP))
 571                 return;
 572
 573         th = __skb_header_pointer(skb, thoff, sizeof(_th), data, hlen, &_th);
 574         if (!th)
 575                 return;
 576
 577         if (unlikely(__tcp_hdrlen(th) < sizeof(_th)))
 578                 return;
 579
 580         key_tcp = skb_flow_dissector_target(flow_dissector,
 581                                             FLOW_DISSECTOR_KEY_TCP,
 582                                             target_container);
 583         key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF));
 584 }
 585
 586 static void
 587 __skb_flow_dissect_ipv4(const struct sk_buff *skb,
 588                         struct flow_dissector *flow_dissector,
 589                         void *target_container, void *data, const struct iphdr *iph)
 590 {
 591         struct flow_dissector_key_ip *key_ip;
 592
 593         if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
 594                 return;
 595
 596         key_ip = skb_flow_dissector_target(flow_dissector,
 597                                            FLOW_DISSECTOR_KEY_IP,
 598                                            target_container);
 599         key_ip->tos = iph->tos;
 600         key_ip->ttl = iph->ttl;
 601 }
 602
 603 static void
 604 __skb_flow_dissect_ipv6(const struct sk_buff *skb,
 605                         struct flow_dissector *flow_dissector,
 606                         void *target_container, void *data, const struct ipv6hdr *iph)
 607 {
 608         struct flow_dissector_key_ip *key_ip;
 609
 610         if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
 611                 return;
 612
 613         key_ip = skb_flow_dissector_target(flow_dissector,
 614                                            FLOW_DISSECTOR_KEY_IP,
 615                                            target_container);
 616         key_ip->tos = ipv6_get_dsfield(iph);
 617         key_ip->ttl = iph->hop_limit;
 618 }
 619
 620 /* Maximum number of protocol headers that can be parsed in
 621  * __skb_flow_dissect
 622  */
 623 #define MAX_FLOW_DISSECT_HDRS   15
 624
 625 static bool skb_flow_dissect_allowed(int *num_hdrs)
 626 {
 627         ++*num_hdrs;
 628
 629         return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS);
 630 }
 631
 632 static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
 633                                      struct flow_dissector *flow_dissector,
 634                                      void *target_container)
 635 {
 636         struct flow_dissector_key_control *key_control;
 637         struct flow_dissector_key_basic *key_basic;
 638         struct flow_dissector_key_addrs *key_addrs;
 639         struct flow_dissector_key_ports *key_ports;
 640
 641         key_control = skb_flow_dissector_target(flow_dissector,
 642                                                 FLOW_DISSECTOR_KEY_CONTROL,
 643                                                 target_container);
 644         key_control->thoff = flow_keys->thoff;
 645         if (flow_keys->is_frag)
 646                 key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 647         if (flow_keys->is_first_frag)
 648                 key_control->flags |= FLOW_DIS_FIRST_FRAG;
 649         if (flow_keys->is_encap)
 650                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 651
 652         key_basic = skb_flow_dissector_target(flow_dissector,
 653                                               FLOW_DISSECTOR_KEY_BASIC,
 654                                               target_container);
 655         key_basic->n_proto = flow_keys->n_proto;
 656         key_basic->ip_proto = flow_keys->ip_proto;
 657
 658         if (flow_keys->addr_proto == ETH_P_IP &&
 659             dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
 660                 key_addrs = skb_flow_dissector_target(flow_dissector,
 661                                                       FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 662                                                       target_container);
 663                 key_addrs->v4addrs.src = flow_keys->ipv4_src;
 664                 key_addrs->v4addrs.dst = flow_keys->ipv4_dst;
 665                 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 666         } else if (flow_keys->addr_proto == ETH_P_IPV6 &&
 667                    dissector_uses_key(flow_dissector,
 668                                       FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 669                 key_addrs = skb_flow_dissector_target(flow_dissector,
 670                                                       FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 671                                                       target_container);
 672                 memcpy(&key_addrs->v6addrs, &flow_keys->ipv6_src,
 673                        sizeof(key_addrs->v6addrs));
 674                 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 675         }
 676
 677         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS)) {
 678                 key_ports = skb_flow_dissector_target(flow_dissector,
 679                                                       FLOW_DISSECTOR_KEY_PORTS,
 680                                                       target_container);
 681                 key_ports->src = flow_keys->sport;
 682                 key_ports->dst = flow_keys->dport;
 683         }
 684 }
 685
 686 bool __skb_flow_bpf_dissect(struct bpf_prog *prog,
 687                             const struct sk_buff *skb,
 688                             struct flow_dissector *flow_dissector,
 689                             struct bpf_flow_keys *flow_keys)
 690 {
 691         struct bpf_skb_data_end cb_saved;
 692         struct bpf_skb_data_end *cb;
 693         u32 result;
 694
 695         /* Note that even though the const qualifier is discarded
 696          * throughout the execution of the BPF program, all changes(the
 697          * control block) are reverted after the BPF program returns.
 698          * Therefore, __skb_flow_dissect does not alter the skb.
 699          */
 700
 701         cb = (struct bpf_skb_data_end *)skb->cb;
 702
 703         /* Save Control Block */
 704         memcpy(&cb_saved, cb, sizeof(cb_saved));
 705         memset(cb, 0, sizeof(*cb));
 706
 707         /* Pass parameters to the BPF program */
 708         memset(flow_keys, 0, sizeof(*flow_keys));
 709         cb->qdisc_cb.flow_keys = flow_keys;
 710         flow_keys->nhoff = skb_network_offset(skb);
 711         flow_keys->thoff = flow_keys->nhoff;
 712
 713         bpf_compute_data_pointers((struct sk_buff *)skb);
 714         result = BPF_PROG_RUN(prog, skb);
 715
 716         /* Restore state */
 717         memcpy(cb, &cb_saved, sizeof(cb_saved));
 718
 719         flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, 0, skb->len);
 720         flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
 721                                    flow_keys->nhoff, skb->len);
 722
 723         return result == BPF_OK;
 724 }
 725
 726 /**
 727  * __skb_flow_dissect - extract the flow_keys struct and return it
 728  * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
 729  * @flow_dissector: list of keys to dissect
 730  * @target_container: target structure to put dissected values into
 731  * @data: raw buffer pointer to the packet, if NULL use skb->data
 732  * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
 733  * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
 734  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
 735  *
 736  * The function will try to retrieve individual keys into target specified
 737  * by flow_dissector from either the skbuff or a raw buffer specified by the
 738  * rest parameters.
 739  *
 740  * Caller must take care of zeroing target container memory.
 741  */
 742 bool __skb_flow_dissect(const struct sk_buff *skb,
 743                         struct flow_dissector *flow_dissector,
 744                         void *target_container,
 745                         void *data, __be16 proto, int nhoff, int hlen,
 746                         unsigned int flags)
 747 {
 748         struct flow_dissector_key_control *key_control;
 749         struct flow_dissector_key_basic *key_basic;
 750         struct flow_dissector_key_addrs *key_addrs;
 751         struct flow_dissector_key_ports *key_ports;
 752         struct flow_dissector_key_icmp *key_icmp;
 753         struct flow_dissector_key_tags *key_tags;
 754         struct flow_dissector_key_vlan *key_vlan;
 755         enum flow_dissect_ret fdret;
 756         enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
 757         int num_hdrs = 0;
 758         u8 ip_proto = 0;
 759         bool ret;
 760
 761         if (!data) {
 762                 data = skb->data;
 763                 proto = skb_vlan_tag_present(skb) ?
 764                          skb->vlan_proto : skb->protocol;
 765                 nhoff = skb_network_offset(skb);
 766                 hlen = skb_headlen(skb);
 767 #if IS_ENABLED(CONFIG_NET_DSA)
 768                 if (unlikely(skb->dev && netdev_uses_dsa(skb->dev))) {
 769                         const struct dsa_device_ops *ops;
 770                         int offset;
 771
 772                         ops = skb->dev->dsa_ptr->tag_ops;
 773                         if (ops->flow_dissect &&
 774                             !ops->flow_dissect(skb, &proto, &offset)) {
 775                                 hlen -= offset;
 776                                 nhoff += offset;
 777                         }
 778                 }
 779 #endif
 780         }
 781
 782         /* It is ensured by skb_flow_dissector_init() that control key will
 783          * be always present.
 784          */
 785         key_control = skb_flow_dissector_target(flow_dissector,
 786                                                 FLOW_DISSECTOR_KEY_CONTROL,
 787                                                 target_container);
 788
 789         /* It is ensured by skb_flow_dissector_init() that basic key will
 790          * be always present.
 791          */
 792         key_basic = skb_flow_dissector_target(flow_dissector,
 793                                               FLOW_DISSECTOR_KEY_BASIC,
 794                                               target_container);
 795
 796         if (skb) {
 797                 struct bpf_flow_keys flow_keys;
 798                 struct bpf_prog *attached = NULL;
 799
 800                 rcu_read_lock();
 801
 802                 if (skb->dev)
 803                         attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog);
 804                 else if (skb->sk)
 805                         attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog);
 806                 else
 807                         WARN_ON_ONCE(1);
 808
 809                 if (attached) {
 810                         ret = __skb_flow_bpf_dissect(attached, skb,
 811                                                      flow_dissector,
 812                                                      &flow_keys);
 813                         __skb_flow_bpf_to_target(&flow_keys, flow_dissector,
 814                                                  target_container);
 815                         rcu_read_unlock();
 816                         return ret;
 817                 }
 818                 rcu_read_unlock();
 819         }
 820
 821         if (dissector_uses_key(flow_dissector,
 822                                FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 823                 struct ethhdr *eth = eth_hdr(skb);
 824                 struct flow_dissector_key_eth_addrs *key_eth_addrs;
 825
 826                 key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 827                                                           FLOW_DISSECTOR_KEY_ETH_ADDRS,
 828                                                           target_container);
 829                 memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 830         }
 831
 832 proto_again:
 833         fdret = FLOW_DISSECT_RET_CONTINUE;
 834
 835         switch (proto) {
 836         case htons(ETH_P_IP): {
 837                 const struct iphdr *iph;
 838                 struct iphdr _iph;
 839
 840                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 841                 if (!iph || iph->ihl < 5) {
 842                         fdret = FLOW_DISSECT_RET_OUT_BAD;
 843                         break;
 844                 }
 845
 846                 nhoff += iph->ihl * 4;
 847
 848                 ip_proto = iph->protocol;
 849
 850                 if (dissector_uses_key(flow_dissector,
 851                                        FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
 852                         key_addrs = skb_flow_dissector_target(flow_dissector,
 853                                                               FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 854                                                               target_container);
 855
 856                         memcpy(&key_addrs->v4addrs, &iph->saddr,
 857                                sizeof(key_addrs->v4addrs));
 858                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 859                 }
 860
 861                 if (ip_is_fragment(iph)) {
 862                         key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 863
 864                         if (iph->frag_off & htons(IP_OFFSET)) {
 865                                 fdret = FLOW_DISSECT_RET_OUT_GOOD;
 866                                 break;
 867                         } else {
 868                                 key_control->flags |= FLOW_DIS_FIRST_FRAG;
 869                                 if (!(flags &
 870                                       FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) {
 871                                         fdret = FLOW_DISSECT_RET_OUT_GOOD;
 872                                         break;
 873                                 }
 874                         }
 875                 }
 876
 877                 __skb_flow_dissect_ipv4(skb, flow_dissector,
 878                                         target_container, data, iph);
 879
 880                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) {
 881                         fdret = FLOW_DISSECT_RET_OUT_GOOD;
 882                         break;
 883                 }
 884
 885                 break;
 886         }
 887         case htons(ETH_P_IPV6): {
 888                 const struct ipv6hdr *iph;
 889                 struct ipv6hdr _iph;
 890
 891                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 892                 if (!iph) {
 893                         fdret = FLOW_DISSECT_RET_OUT_BAD;
 894                         break;
 895                 }
 896
 897                 ip_proto = iph->nexthdr;
 898                 nhoff += sizeof(struct ipv6hdr);
 899
 900                 if (dissector_uses_key(flow_dissector,
 901                                        FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 902                         key_addrs = skb_flow_dissector_target(flow_dissector,
 903                                                               FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 904                                                               target_container);
 905
 906                         memcpy(&key_addrs->v6addrs, &iph->saddr,
 907                                sizeof(key_addrs->v6addrs));
 908                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 909                 }
 910
 911                 if ((dissector_uses_key(flow_dissector,
 912                                         FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
 913                      (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
 914                     ip6_flowlabel(iph)) {
 915                         __be32 flow_label = ip6_flowlabel(iph);
 916
 917                         if (dissector_uses_key(flow_dissector,
 918                                                FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
 919                                 key_tags = skb_flow_dissector_target(flow_dissector,
 920                                                                      FLOW_DISSECTOR_KEY_FLOW_LABEL,
 921                                                                      target_container);
 922                                 key_tags->flow_label = ntohl(flow_label);
 923                         }
 924                         if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) {
 925                                 fdret = FLOW_DISSECT_RET_OUT_GOOD;
 926                                 break;
 927                         }
 928                 }
 929
 930                 __skb_flow_dissect_ipv6(skb, flow_dissector,
 931                                         target_container, data, iph);
 932
 933                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 934                         fdret = FLOW_DISSECT_RET_OUT_GOOD;
 935
 936                 break;
 937         }
 938         case htons(ETH_P_8021AD):
 939         case htons(ETH_P_8021Q): {
 940                 const struct vlan_hdr *vlan = NULL;
 941                 struct vlan_hdr _vlan;
 942                 __be16 saved_vlan_tpid = proto;
 943
 944                 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX &&
 945                     skb && skb_vlan_tag_present(skb)) {
 946                         proto = skb->protocol;
 947                 } else {
 948                         vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
 949                                                     data, hlen, &_vlan);
 950                         if (!vlan) {
 951                                 fdret = FLOW_DISSECT_RET_OUT_BAD;
 952                                 break;
 953                         }
 954
 955                         proto = vlan->h_vlan_encapsulated_proto;
 956                         nhoff += sizeof(*vlan);
 957                 }
 958
 959                 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) {
 960                         dissector_vlan = FLOW_DISSECTOR_KEY_VLAN;
 961                 } else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) {
 962                         dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN;
 963                 } else {
 964                         fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
 965                         break;
 966                 }
 967
 968                 if (dissector_uses_key(flow_dissector, dissector_vlan)) {
 969                         key_vlan = skb_flow_dissector_target(flow_dissector,
 970                                                              dissector_vlan,
 971                                                              target_container);
 972
 973                         if (!vlan) {
 974                                 key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
 975                                 key_vlan->vlan_priority = skb_vlan_tag_get_prio(skb);
 976                         } else {
 977                                 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
 978                                         VLAN_VID_MASK;
 979                                 key_vlan->vlan_priority =
 980                                         (ntohs(vlan->h_vlan_TCI) &
 981                                          VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
 982                         }
 983                         key_vlan->vlan_tpid = saved_vlan_tpid;
 984                 }
 985
 986                 fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
 987                 break;
 988         }
 989         case htons(ETH_P_PPP_SES): {
 990                 struct {
 991                         struct pppoe_hdr hdr;
 992                         __be16 proto;
 993                 } *hdr, _hdr;
 994                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 995                 if (!hdr) {
 996                         fdret = FLOW_DISSECT_RET_OUT_BAD;
 997                         break;
 998                 }
 999
1000                 proto = hdr->proto;
1001                 nhoff += PPPOE_SES_HLEN;
1002                 switch (proto) {
1003                 case htons(PPP_IP):
1004                         proto = htons(ETH_P_IP);
1005                         fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1006                         break;
1007                 case htons(PPP_IPV6):
1008                         proto = htons(ETH_P_IPV6);
1009                         fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1010                         break;
1011                 default:
1012                         fdret = FLOW_DISSECT_RET_OUT_BAD;
1013                         break;
1014                 }
1015                 break;
1016         }
1017         case htons(ETH_P_TIPC): {
1018                 struct tipc_basic_hdr *hdr, _hdr;
1019
1020                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr),
1021                                            data, hlen, &_hdr);
1022                 if (!hdr) {
1023                         fdret = FLOW_DISSECT_RET_OUT_BAD;
1024                         break;
1025                 }
1026
1027                 if (dissector_uses_key(flow_dissector,
1028                                        FLOW_DISSECTOR_KEY_TIPC)) {
1029                         key_addrs = skb_flow_dissector_target(flow_dissector,
1030                                                               FLOW_DISSECTOR_KEY_TIPC,
1031                                                               target_container);
1032                         key_addrs->tipckey.key = tipc_hdr_rps_key(hdr);
1033                         key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC;
1034                 }
1035                 fdret = FLOW_DISSECT_RET_OUT_GOOD;
1036                 break;
1037         }
1038
1039         case htons(ETH_P_MPLS_UC):
1040         case htons(ETH_P_MPLS_MC):
1041                 fdret = __skb_flow_dissect_mpls(skb, flow_dissector,
1042                                                 target_container, data,
1043                                                 nhoff, hlen);
1044                 break;
1045         case htons(ETH_P_FCOE):
1046                 if ((hlen - nhoff) < FCOE_HEADER_LEN) {
1047                         fdret = FLOW_DISSECT_RET_OUT_BAD;
1048                         break;
1049                 }
1050
1051                 nhoff += FCOE_HEADER_LEN;
1052                 fdret = FLOW_DISSECT_RET_OUT_GOOD;
1053                 break;
1054
1055         case htons(ETH_P_ARP):
1056         case htons(ETH_P_RARP):
1057                 fdret = __skb_flow_dissect_arp(skb, flow_dissector,
1058                                                target_container, data,
1059                                                nhoff, hlen);
1060                 break;
1061
1062         case htons(ETH_P_BATMAN):
1063                 fdret = __skb_flow_dissect_batadv(skb, key_control, data,
1064                                                   &proto, &nhoff, hlen, flags);
1065                 break;
1066
1067         default:
1068                 fdret = FLOW_DISSECT_RET_OUT_BAD;
1069                 break;
1070         }
1071
1072         /* Process result of proto processing */
1073         switch (fdret) {
1074         case FLOW_DISSECT_RET_OUT_GOOD:
1075                 goto out_good;
1076         case FLOW_DISSECT_RET_PROTO_AGAIN:
1077                 if (skb_flow_dissect_allowed(&num_hdrs))
1078                         goto proto_again;
1079                 goto out_good;
1080         case FLOW_DISSECT_RET_CONTINUE:
1081         case FLOW_DISSECT_RET_IPPROTO_AGAIN:
1082                 break;
1083         case FLOW_DISSECT_RET_OUT_BAD:
1084         default:
1085                 goto out_bad;
1086         }
1087
1088 ip_proto_again:
1089         fdret = FLOW_DISSECT_RET_CONTINUE;
1090
1091         switch (ip_proto) {
1092         case IPPROTO_GRE:
1093                 fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector,
1094                                                target_container, data,
1095                                                &proto, &nhoff, &hlen, flags);
1096                 break;
1097
1098         case NEXTHDR_HOP:
1099         case NEXTHDR_ROUTING:
1100         case NEXTHDR_DEST: {
1101                 u8 _opthdr[2], *opthdr;
1102
1103                 if (proto != htons(ETH_P_IPV6))
1104                         break;
1105
1106                 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
1107                                               data, hlen, &_opthdr);
1108                 if (!opthdr) {
1109                         fdret = FLOW_DISSECT_RET_OUT_BAD;
1110                         break;
1111                 }
1112
1113                 ip_proto = opthdr[0];
1114                 nhoff += (opthdr[1] + 1) << 3;
1115
1116                 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
1117                 break;
1118         }
1119         case NEXTHDR_FRAGMENT: {
1120                 struct frag_hdr _fh, *fh;
1121
1122                 if (proto != htons(ETH_P_IPV6))
1123                         break;
1124
1125                 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
1126                                           data, hlen, &_fh);
1127
1128                 if (!fh) {
1129                         fdret = FLOW_DISSECT_RET_OUT_BAD;
1130                         break;
1131                 }
1132
1133                 key_control->flags |= FLOW_DIS_IS_FRAGMENT;
1134
1135                 nhoff += sizeof(_fh);
1136                 ip_proto = fh->nexthdr;
1137
1138                 if (!(fh->frag_off & htons(IP6_OFFSET))) {
1139                         key_control->flags |= FLOW_DIS_FIRST_FRAG;
1140                         if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {
1141                                 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
1142                                 break;
1143                         }
1144                 }
1145
1146                 fdret = FLOW_DISSECT_RET_OUT_GOOD;
1147                 break;
1148         }
1149         case IPPROTO_IPIP:
1150                 proto = htons(ETH_P_IP);
1151
1152                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
1153                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
1154                         fdret = FLOW_DISSECT_RET_OUT_GOOD;
1155                         break;
1156                 }
1157
1158                 fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1159                 break;
1160
1161         case IPPROTO_IPV6:
1162                 proto = htons(ETH_P_IPV6);
1163
1164                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
1165                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
1166                         fdret = FLOW_DISSECT_RET_OUT_GOOD;
1167                         break;
1168                 }
1169
1170                 fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1171                 break;
1172
1173
1174         case IPPROTO_MPLS:
1175                 proto = htons(ETH_P_MPLS_UC);
1176                 fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1177                 break;
1178
1179         case IPPROTO_TCP:
1180                 __skb_flow_dissect_tcp(skb, flow_dissector, target_container,
1181                                        data, nhoff, hlen);
1182                 break;
1183
1184         default:
1185                 break;
1186         }
1187
1188         if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS) &&
1189             !(key_control->flags & FLOW_DIS_IS_FRAGMENT)) {
1190                 key_ports = skb_flow_dissector_target(flow_dissector,
1191                                                       FLOW_DISSECTOR_KEY_PORTS,
1192                                                       target_container);
1193                 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
1194                                                         data, hlen);
1195         }
1196
1197         if (dissector_uses_key(flow_dissector,
1198                                FLOW_DISSECTOR_KEY_ICMP)) {
1199                 key_icmp = skb_flow_dissector_target(flow_dissector,
1200                                                      FLOW_DISSECTOR_KEY_ICMP,
1201                                                      target_container);
1202                 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
1203         }
1204
1205         /* Process result of IP proto processing */
1206         switch (fdret) {
1207         case FLOW_DISSECT_RET_PROTO_AGAIN:
1208                 if (skb_flow_dissect_allowed(&num_hdrs))
1209                         goto proto_again;
1210                 break;
1211         case FLOW_DISSECT_RET_IPPROTO_AGAIN:
1212                 if (skb_flow_dissect_allowed(&num_hdrs))
1213                         goto ip_proto_again;
1214                 break;
1215         case FLOW_DISSECT_RET_OUT_GOOD:
1216         case FLOW_DISSECT_RET_CONTINUE:
1217                 break;
1218         case FLOW_DISSECT_RET_OUT_BAD:
1219         default:
1220                 goto out_bad;
1221         }
1222
1223 out_good:
1224         ret = true;
1225
1226 out:
1227         key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
1228         key_basic->n_proto = proto;
1229         key_basic->ip_proto = ip_proto;
1230
1231         return ret;
1232
1233 out_bad:
1234         ret = false;
1235         goto out;
1236 }
1237 EXPORT_SYMBOL(__skb_flow_dissect);
1238
1239 static u32 hashrnd __read_mostly;
1240 static __always_inline void __flow_hash_secret_init(void)
1241 {
1242         net_get_random_once(&hashrnd, sizeof(hashrnd));
1243 }
1244
1245 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length,
1246                                              u32 keyval)
1247 {
1248         return jhash2(words, length, keyval);
1249 }
1250
1251 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow)
1252 {
1253         const void *p = flow;
1254
1255         BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
1256         return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET);
1257 }
1258
1259 static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
1260 {
1261         size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
1262         BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
1263         BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
1264                      sizeof(*flow) - sizeof(flow->addrs));
1265
1266         switch (flow->control.addr_type) {
1267         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1268                 diff -= sizeof(flow->addrs.v4addrs);
1269                 break;
1270         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1271                 diff -= sizeof(flow->addrs.v6addrs);
1272                 break;
1273         case FLOW_DISSECTOR_KEY_TIPC:
1274                 diff -= sizeof(flow->addrs.tipckey);
1275                 break;
1276         }
1277         return (sizeof(*flow) - diff) / sizeof(u32);
1278 }
1279
1280 __be32 flow_get_u32_src(const struct flow_keys *flow)
1281 {
1282         switch (flow->control.addr_type) {
1283         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1284                 return flow->addrs.v4addrs.src;
1285         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1286                 return (__force __be32)ipv6_addr_hash(
1287                         &flow->addrs.v6addrs.src);
1288         case FLOW_DISSECTOR_KEY_TIPC:
1289                 return flow->addrs.tipckey.key;
1290         default:
1291                 return 0;
1292         }
1293 }
1294 EXPORT_SYMBOL(flow_get_u32_src);
1295
1296 __be32 flow_get_u32_dst(const struct flow_keys *flow)
1297 {
1298         switch (flow->control.addr_type) {
1299         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1300                 return flow->addrs.v4addrs.dst;
1301         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1302                 return (__force __be32)ipv6_addr_hash(
1303                         &flow->addrs.v6addrs.dst);
1304         default:
1305                 return 0;
1306         }
1307 }
1308 EXPORT_SYMBOL(flow_get_u32_dst);
1309
1310 static inline void __flow_hash_consistentify(struct flow_keys *keys)
1311 {
1312         int addr_diff, i;
1313
1314         switch (keys->control.addr_type) {
1315         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1316                 addr_diff = (__force u32)keys->addrs.v4addrs.dst -
1317                             (__force u32)keys->addrs.v4addrs.src;
1318                 if ((addr_diff < 0) ||
1319                     (addr_diff == 0 &&
1320                      ((__force u16)keys->ports.dst <
1321                       (__force u16)keys->ports.src))) {
1322                         swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
1323                         swap(keys->ports.src, keys->ports.dst);
1324                 }
1325                 break;
1326         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1327                 addr_diff = memcmp(&keys->addrs.v6addrs.dst,
1328                                    &keys->addrs.v6addrs.src,
1329                                    sizeof(keys->addrs.v6addrs.dst));
1330                 if ((addr_diff < 0) ||
1331                     (addr_diff == 0 &&
1332                      ((__force u16)keys->ports.dst <
1333                       (__force u16)keys->ports.src))) {
1334                         for (i = 0; i < 4; i++)
1335                                 swap(keys->addrs.v6addrs.src.s6_addr32[i],
1336                                      keys->addrs.v6addrs.dst.s6_addr32[i]);
1337                         swap(keys->ports.src, keys->ports.dst);
1338                 }
1339                 break;
1340         }
1341 }
1342
1343 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
1344 {
1345         u32 hash;
1346
1347         __flow_hash_consistentify(keys);
1348
1349         hash = __flow_hash_words(flow_keys_hash_start(keys),
1350                                  flow_keys_hash_length(keys), keyval);
1351         if (!hash)
1352                 hash = 1;
1353
1354         return hash;
1355 }
1356
1357 u32 flow_hash_from_keys(struct flow_keys *keys)
1358 {
1359         __flow_hash_secret_init();
1360         return __flow_hash_from_keys(keys, hashrnd);
1361 }
1362 EXPORT_SYMBOL(flow_hash_from_keys);
1363
1364 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
1365                                   struct flow_keys *keys, u32 keyval)
1366 {
1367         skb_flow_dissect_flow_keys(skb, keys,
1368                                    FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
1369
1370         return __flow_hash_from_keys(keys, keyval);
1371 }
1372
1373 struct _flow_keys_digest_data {
1374         __be16  n_proto;
1375         u8      ip_proto;
1376         u8      padding;
1377         __be32  ports;
1378         __be32  src;
1379         __be32  dst;
1380 };
1381
1382 void make_flow_keys_digest(struct flow_keys_digest *digest,
1383                            const struct flow_keys *flow)
1384 {
1385         struct _flow_keys_digest_data *data =
1386             (struct _flow_keys_digest_data *)digest;
1387
1388         BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
1389
1390         memset(digest, 0, sizeof(*digest));
1391
1392         data->n_proto = flow->basic.n_proto;
1393         data->ip_proto = flow->basic.ip_proto;
1394         data->ports = flow->ports.ports;
1395         data->src = flow->addrs.v4addrs.src;
1396         data->dst = flow->addrs.v4addrs.dst;
1397 }
1398 EXPORT_SYMBOL(make_flow_keys_digest);
1399
1400 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
1401
1402 u32 __skb_get_hash_symmetric(const struct sk_buff *skb)
1403 {
1404         struct flow_keys keys;
1405
1406         __flow_hash_secret_init();
1407
1408         memset(&keys, 0, sizeof(keys));
1409         __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys,
1410                            NULL, 0, 0, 0,
1411                            FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
1412
1413         return __flow_hash_from_keys(&keys, hashrnd);
1414 }
1415 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric);
1416
1417 /**
1418  * __skb_get_hash: calculate a flow hash
1419  * @skb: sk_buff to calculate flow hash from
1420  *
1421  * This function calculates a flow hash based on src/dst addresses
1422  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
1423  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
1424  * if hash is a canonical 4-tuple hash over transport ports.
1425  */
1426 void __skb_get_hash(struct sk_buff *skb)
1427 {
1428         struct flow_keys keys;
1429         u32 hash;
1430
1431         __flow_hash_secret_init();
1432
1433         hash = ___skb_get_hash(skb, &keys, hashrnd);
1434
1435         __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1436 }
1437 EXPORT_SYMBOL(__skb_get_hash);
1438
1439 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
1440 {
1441         struct flow_keys keys;
1442
1443         return ___skb_get_hash(skb, &keys, perturb);
1444 }
1445 EXPORT_SYMBOL(skb_get_hash_perturb);
1446
1447 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1448                    const struct flow_keys_basic *keys, int hlen)
1449 {
1450         u32 poff = keys->control.thoff;
1451
1452         /* skip L4 headers for fragments after the first */
1453         if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
1454             !(keys->control.flags & FLOW_DIS_FIRST_FRAG))
1455                 return poff;
1456
1457         switch (keys->basic.ip_proto) {
1458         case IPPROTO_TCP: {
1459                 /* access doff as u8 to avoid unaligned access */
1460                 const u8 *doff;
1461                 u8 _doff;
1462
1463                 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
1464                                             data, hlen, &_doff);
1465                 if (!doff)
1466                         return poff;
1467
1468                 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
1469                 break;
1470         }
1471         case IPPROTO_UDP:
1472         case IPPROTO_UDPLITE:
1473                 poff += sizeof(struct udphdr);
1474                 break;
1475         /* For the rest, we do not really care about header
1476          * extensions at this point for now.
1477          */
1478         case IPPROTO_ICMP:
1479                 poff += sizeof(struct icmphdr);
1480                 break;
1481         case IPPROTO_ICMPV6:
1482                 poff += sizeof(struct icmp6hdr);
1483                 break;
1484         case IPPROTO_IGMP:
1485                 poff += sizeof(struct igmphdr);
1486                 break;
1487         case IPPROTO_DCCP:
1488                 poff += sizeof(struct dccp_hdr);
1489                 break;
1490         case IPPROTO_SCTP:
1491                 poff += sizeof(struct sctphdr);
1492                 break;
1493         }
1494
1495         return poff;
1496 }
1497
1498 /**
1499  * skb_get_poff - get the offset to the payload
1500  * @skb: sk_buff to get the payload offset from
1501  *
1502  * The function will get the offset to the payload as far as it could
1503  * be dissected.  The main user is currently BPF, so that we can dynamically
1504  * truncate packets without needing to push actual payload to the user
1505  * space and can analyze headers only, instead.
1506  */
1507 u32 skb_get_poff(const struct sk_buff *skb)
1508 {
1509         struct flow_keys_basic keys;
1510
1511         if (!skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0))
1512                 return 0;
1513
1514         return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
1515 }
1516
1517 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
1518 {
1519         memset(keys, 0, sizeof(*keys));
1520
1521         memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
1522             sizeof(keys->addrs.v6addrs.src));
1523         memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
1524             sizeof(keys->addrs.v6addrs.dst));
1525         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1526         keys->ports.src = fl6->fl6_sport;
1527         keys->ports.dst = fl6->fl6_dport;
1528         keys->keyid.keyid = fl6->fl6_gre_key;
1529         keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
1530         keys->basic.ip_proto = fl6->flowi6_proto;
1531
1532         return flow_hash_from_keys(keys);
1533 }
1534 EXPORT_SYMBOL(__get_hash_from_flowi6);
1535
1536 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
1537         {
1538                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1539                 .offset = offsetof(struct flow_keys, control),
1540         },
1541         {
1542                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1543                 .offset = offsetof(struct flow_keys, basic),
1544         },
1545         {
1546                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1547                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
1548         },
1549         {
1550                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1551                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
1552         },
1553         {
1554                 .key_id = FLOW_DISSECTOR_KEY_TIPC,
1555                 .offset = offsetof(struct flow_keys, addrs.tipckey),
1556         },
1557         {
1558                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
1559                 .offset = offsetof(struct flow_keys, ports),
1560         },
1561         {
1562                 .key_id = FLOW_DISSECTOR_KEY_VLAN,
1563                 .offset = offsetof(struct flow_keys, vlan),
1564         },
1565         {
1566                 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
1567                 .offset = offsetof(struct flow_keys, tags),
1568         },
1569         {
1570                 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
1571                 .offset = offsetof(struct flow_keys, keyid),
1572         },
1573 };
1574
1575 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
1576         {
1577                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1578                 .offset = offsetof(struct flow_keys, control),
1579         },
1580         {
1581                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1582                 .offset = offsetof(struct flow_keys, basic),
1583         },
1584         {
1585                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1586                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
1587         },
1588         {
1589                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1590                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
1591         },
1592         {
1593                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
1594                 .offset = offsetof(struct flow_keys, ports),
1595         },
1596 };
1597
1598 static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = {
1599         {
1600                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1601                 .offset = offsetof(struct flow_keys, control),
1602         },
1603         {
1604                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1605                 .offset = offsetof(struct flow_keys, basic),
1606         },
1607 };
1608
1609 struct flow_dissector flow_keys_dissector __read_mostly;
1610 EXPORT_SYMBOL(flow_keys_dissector);
1611
1612 struct flow_dissector flow_keys_basic_dissector __read_mostly;
1613 EXPORT_SYMBOL(flow_keys_basic_dissector);
1614
1615 static int __init init_default_flow_dissectors(void)
1616 {
1617         skb_flow_dissector_init(&flow_keys_dissector,
1618                                 flow_keys_dissector_keys,
1619                                 ARRAY_SIZE(flow_keys_dissector_keys));
1620         skb_flow_dissector_init(&flow_keys_dissector_symmetric,
1621                                 flow_keys_dissector_symmetric_keys,
1622                                 ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
1623         skb_flow_dissector_init(&flow_keys_basic_dissector,
1624                                 flow_keys_basic_dissector_keys,
1625                                 ARRAY_SIZE(flow_keys_basic_dissector_keys));
1626         return 0;
1627 }
1628
1629 core_initcall(init_default_flow_dissectors);